Worms and Flies - How These Not-So-Distant Cousins Help Us Understand Ourselves

January 12, 2017

by Meghan Krizus

“Wait, you study bugs? I thought you said you were a cancer researcher!” It’s something that scientists who work with model organisms hear a little more often than we’d like. But for good reason—at first glance, it might be difficult to see why researching nematodes or fruit flies has any significance to human health. But if we look closer, it becomes apparent that work done with Caenorhabditis elegans (C. elegans affectionately called “worm” by its devotees) and Drosophila melanogaster (likewise nicknamed “fly”) helps us understand and treat human disease.

Model organisms allow us to see cellular processes happening in real time. Here, a C. elegans embryo is undergoing its first mitotic divisions. The spindle fibres are marked with tubulin tagged with green fluorescent protein (GFP). This strain (AZ244) was provided by the CGC, which is funded by the NIH Office of Research Infrastructure Programs (P40 OD010440) (click the image for larger version)

Initially, it might seem as though we and our nematode and insect cousins couldn’t possibly be more different. After all, humans can’t share much with a miniscule soil nematode or a diminutive fruit fly, right?

Wrong! Despite our differences in size from the microscopic C. elegans or the milimetres-long Drosophila, we have much in common with these tiny animals. The BBC reported in 2000, for instance, that Drosophila shares nearly 60% of its genes with humans; likewise, scientists have discovered that C. elegansshares 35% of its genes with us. These similarities mean that advances made in the genetics of C. elegans and Drosophila can help us understand how the same genes work in humans. Since deleterious mutations in the human genome can cause severe human diseases like Huntington’s, determining how such mutations may affect worms or flies can help us learn about and treat human disease.

Beyond our genes, we also share physiological characteristics with these organisms. Just as we do, both C. elegans and Drosophila have complicated muscular, reproductive, digestive, and nervous systems. And just as we may be afflicted by disease in any of these systems, so too can C. elegans and Drosophila. So if we can understand what causes infertility in flies or tumours in worms, we can take steps toward understanding why we, too, experience such health issues.

“So why not just study humans?” It’s another question that scientists often hear. Of course, studying humans themselves is crucial, but using model organisms can provide a complementary tool to understanding human disease.

Our interest in these organisms can be best understood by what we call them: model organisms. Just as creating a model of a building might help an architect bring their final design to life, so too does studying model organisms help scientists understand us. In this way, we can use the model of a worm or a fly just as an architect would use theirs—to examine their project on a small, manageable scale that is fast and easy to manipulate, before moving up to the larger and more complex one.

And certainly worms and flies are faster and easier to manipulate than humans. Their small size allows scientists to observe an entire organism with ease, allowing us to examine whole tissues and to study them in vivo. In combination with in vitro culture of human cell lines, this enables scientists to study both the tissue alone, as well as how it exists in the context of a whole, living organism.

Not to mention that C. elegans and Drosophila produce hundreds of progeny that mature exceptionally quickly, saving time and money and speeding the process of discovery. A juvenile fruit fly, for instance, matures in less than two weeks. For a nematode, the process is even faster; a C. elegans embryo can be laid, hatch, and grow to adulthood in just over two days. This allows scientists to work quickly, making discoveries and observations in a matter of months that could take decades in humans. And when human health is at stake, time is certainly of the essence.

Here at the Lunenfeld-Tanenbaum Research Institute, we understand and value our model organisms for what they can teach us about ourselves. Under the supervision of our award-winning team of senior investigators, scientists at the LTRI use model organisms to study a whole host of human health concerns including (but not limited to): neurobiology and cancer biology. After all, we understand how our not-so-distant relatives of flies and worms can provide the keys to understanding and curing human disease.

Want to know more?

Resources open to scientists are also open to the public! Check out WormAtlas, WormBase, FlyAtlas, and FlyBase: